Ecology. Throughout the open Yungas and Tucuman-Bolivian montane, prepuna and puna; exposed sites, on soil and rocks, frequent in disturbed areas, e.g., road banks. Elevation. (788)1050-4980 m. Distribution. Bolivia: Chuquisaca, Cochabamba, La Paz, Potosí, Santa Cruz, Tarija. World range: Widespread.
Polytrichum juniperinum is readily distinguished by the upper marginal lamina folded over ventral surface of the leaf limb. Plants vary considerable in stature, from 1 cm to 15 cm tall. Smaller plants are often associated with wind swept, exposed localities in the puna and open high montane, larger plants found in more mesic montane localities. This species is treated broadly here (but see Walther, 1934). Some collections observed in Bolivia and elsewhere in the tropical Andes approach the form referred to as var. affine (Funck) Brid. (= Polytrichum strictum Menzies ex Brid.). This variety is characterized stems densely covered by whitish rhizoids. A number of collections are often mixed, some plants densely tomentose, others partially covered and others naked. Rather amazing that only three species were previously described as new species from Bolivia: Polytrichum angusticaule Müll. Hal. ex E. Britton, P. cuspidigerum Schimp. ex E. Britton and P. tumescens Müll. Hal.
Specimens. Chuquisaca: Churchill & Churchill 20718 (MO, USZ); La Paz: Fuentes 4955 (BOLV, HSB, LPB, MO, USZ).